TECHNICAL LIBRARY

Featuring more than 1,000 searchable technical papers, business features, country commentaries and fashion articles from editions of World Leather going back to 2002. The papers are categorised into nine topics to make the library easy to navigate.

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Technical Articles

RAW MATERIAL: Raw hides/skins and preservation

72 Items Found

Management of microbial growth on hides and leather (part two)This extensive paper from ATC examines the subject of microbial growth in the tannery and how to
combat it. Part one which included Figures 1-12 appeared in World Leather October-November 2019;
part two continues its scrutiny of the mechanisms of action of different fungicides.

World Leather - Dec/Jan 2020

Management of microbial growth on hides and leather (part two)This extensive paper from ATC examines the subject of microbial growth in the tannery and how to
combat it. Part one which included Figures 1-12 appeared in World Leather October-November 2019;
part two continues its scrutiny of the mechanisms of action of different

World Leather - Dec/Jan 2019

Management of microbial growth on hides and leather (part one)Leather is a natural product susceptible to microbial growth owing to the presence of proteins and
lipids. Tanneries provide an environment that lends itself to microbiological development since there
are sources of nutrients and water throughout the manufacturing process as shown in Fig. 1 below.
Pickled pelts, wet blue hides and vegetable-tanned moist leathers are especially prone to microbial
attack, even when stored or shipped.

World Leather - Oct/Nov 2019

Reducing natural leather wrinkles to maximise cutting yieldWrinkles are genetically programmed in any animal and appear as the breakdown of
collagen occurs with age. The degradation is achieved by an immutable biochemistry that,
over time, creates collagen-related aging compounds that are increasingly dry, weak and
brittle. ATC Tannery Chemicals has developed a product for use in the beamhouse that it
states can reduce natural animal wrinkles and help maximise cutting yields without having to
perform heavy buffing and finishing processes. The company argues that this can improve
uniformity from hide to hide or skin to skin.

World Leather - Aug/Sept 2019

Automated grading – removing the subjectivityDVLeather SRL was formed after Detect Vision, a Canadian company specialising
in computer vision, and Feltre, an Italian provider of automation and transportation
systems for the tanning industry, decided to combine their expertise. Combining
traditional methods and advanced technology, DVLeather SRL claims to have
created “a real technological breakthrough” in grading hides.

World Leather - Aug/Sept 2019

Hides go to wasteDemand for high-quality leather remains strong, but no one in the global
industry can be in any doubt that lower-value material is harder to sell
than at any time in living memory. As a result, what we thought would
never happen has come to pass: hides really are going to waste.

World Leather - Apr/May 2019

Arzignano is the leather industry’s Silicon ValleyThe much travelled international sales director of leather chemicals group GSC, Diego Cisco, argues
that the Arzignano tanning cluster, near his company’s headquarters in northern Italy, can offer an
example of leadership, innovation and entrepreneurial spirit to the entire global leather industry.

World Leather - Jun/July 2018

Waterproofing innovationLanxess has introduced a self-emulsifying polymer that it says can help tanners produce leather with high levels of waterproofness from variable raw material.

World Leather - Apr/May 2018

Reduction of salt usage in leather processingThe issue of salt usage is one which the leather industry is still fighting to address.
World Leather technical editor Mike Tomkin delves deeper into why it poses such a
big problem and calls on the industry to do more to tackle it head-on.

World Leather - Apr/May 2018

Salting hides needs to stopMeat consumption will continue and hides will continue to move from abattoirs into leather production. In
this article, based on an influential speech he made at the third World Leather Congress in Shanghai in
2017, World Leather’s publisher and chief executive, Simon Yarwood, argues that what must not continue
is the practice of salting those hides and shipping them across the oceans of the world so that the
excess salt becomes someone else’s environmental problem.

World Leather - Apr/May 2018

Smit & zoon has big plans for IndiaAt the recent India International Leather Fair (IILF) in Chennai, World Leather sat
down with the CEO of Smit & zoon, Hans van Haarst, to discuss the leather
chemical manufacturer’s plans for the Indian market, its Product Passport and
the motivations behind its acquisition of Italian chemicals producer Codyeco.

Developments in fatliquoringAt February’s IULTCS Congress in Chennai, Dirick von Behr, technical manager for leather at chemicals
manufacturer Smit & zoon, presented a paper entitled “Method for determining the optimised exhaustion of
fatliquors to minimise the ETP-inflow”. The paper referenced the upcoming changes in German regulations
for the treatment of tannery wastewater. World Leather sat down with Mr von Behr to find out more.

World Leather - Apr/May 2017

greenLIFE 3: New renewable tanning technologiesGreen Leather Industry for the Environment (greenLIFE) is a project run by a
group of industry partners in Italy’s Arzignano tanning cluster. The project
partners have committed to sharing their findings by publishing a series of
papers in World Leather. The third of six greenLIFE articles comes courtesy of
chemical supplier Ikem, one of the project’s partners.

World Leather - Apr/May 2017

Tackling “veininess”, Part twoThe second and final part of a paper from Lanxess examining the best strategy for addressing the problem
of veininess in hides. The first part appeared in World Leather December 2016-January 2017.

World Leather - Feb/Mar 2017

ReVeal – the Dutch veal and calfskin industry opens its doorsLeather chemicals manufacturer Stahl hosted a one-day event called ReVeal last November.
The aim was to give finished product brands up-to-date information about transparency
and traceability in the leather supply chain, with the focus firmly on Dutch calf leather.

World Leather - Dec/Jan 2016

Tackling “veininess”, Part oneVeininess usually refers to an unsightly defect visible on the
grain linked to sunken veins. Nevertheless, prominent
arteries too can result in downgrading of the leather, so it
would be better to refer to “blood vessels”; however, for the sake
of consistency the most commonly observed defect will be
referred to as veininess.

World Leather - Dec/Jan 2016

Focus on Automotive Leather: Better from BrazilImprovements in livestock farming and in raw material handling are helping Brazilian packers produce better quality raw material, argues JBS Couros’s Guilherme Motta. He believes it could be time for automotive companies to make more use of Brazilian hides.

Studies on the determination of soiling and cleaning behaviour of leather. Part 1: Inter-laboratory test on soiling and cleaning behaviour of leatherA main task of the VGCT Commission “Leather Testing and Assessment” is the detailed examination for the
determination of physical and colour fastness properties of leather, especially in terms of procedures. The intention
is to detect performance characteristics of the procedures and to reveal and eliminate possible sources of error.
Due to the trend for light-coloured leather for upholstery in the automotive and furniture sector, the soiling and
cleaning behaviour of leather and its determination gain in importance.
From the multiplicity of available test procedures for the characterisation of soiling and cleaning behaviour, the
procedure VDA 230-212 was chosen and considered closely by means of an inter-laboratory test programme. In
the context each procedural step was examined closely with regard to their impact on the final result of the test.
Part 1 presents the results of the inter-laboratory test on soiling and cleaning behaviour of leather.
Part 2 (to be published in World Leather later in 2016) will deal with the validation of
an optimised mechanical cleaning step.

The rise of automotive leatherAs car manufacturers around the world report record sales and expanding
production, the future looks rosy for their leather suppliers. However, it is
not all plain sailing: battles over raw material are set to intensify and
leather will have work to keep its place in the hearts of consumers.

World Leather - Feb/Mar 2015

Avoiding poor tensile strength valuesThe tensile strength of leather is a physical-mechanical
property which is directly linked to the properties of the
raw hide, chemical processing, and the physical
operations involved in manufacturing a particular leather.

World Leather - Feb/Mar 2015

Somalia: The Berbera TanneryThe region that today encompasses Somaliland was home
to the earliest civilization in the region. The most salient
feature of this ancient civilization is thought to be the
Laas Geel Neolithic cave paintings, which are among the oldest
such rock art in Africa. These cave paintings are located in a site
outside Hargeisa, the capital of the Somaliland region, and were
untouched and intact for nearly 5-10,000 years until their
recent rediscovery at the end of 2002.

Tanneries for tourists but not for real leather manufactureThe conversion of raw skins into leather as a durable and protective product is among the earliest of crafts. Leather manufacture has now evolved into a sophisticated and
technically developed industry but there are a few remaining examples that provide an illustration of early practices.

World Leather - Oct/Nov 2013

Improvement of sheepskin quality after treatment against cockle with diazinonInfestations of lice and keds are the cause of cockle defect and the reason for considerable loss in the value of sheepskins in Ethiopia. The findings from extensive trials on two breeds of sheep shows that the cockle defect can be eradicated, coupled with a significant improvement of both skin grades and value.

World Leather - Apr/May 2012

Innovation Part 1: Recycling and regenerationTwenty world standard tanneries have opened their doors for in-depth study as part of Tannery of the Year Awards 2009 and 2011. Considerable technical information has been published in World Leather following these visits, and there has been an emphasis on environmental aspects. This article is the first in a series that picks out some of the highlights from the innovation stories these top tanneries have shared with us.

World Leather - Oct/Nov 2011

Expert questions Uttar Pradesh pollution ‘breakthrough’The central pollution control board of the Indian state of Uttar Pradesh claims to have come up with a new, salt-free method of preserving hides and has talked of compelling tanners to put the new technology into practice. But a seasoned industry observer has expressed doubt about the viability of the idea.

World Leather - Aug/Sep 2011

Anthrax: danger in raw hidesAnthrax can be transmitted to human beings via endospores by entering broken skin and germinating there, being inhaled and germinating in the lungs or by being eaten and germinating in the gastrointestinal tract. Spores can form after the hide of an infected animal is flayed.

Small moulds can cause big problemsAsignificant cause of loss in value in leather processing
is due to fungal or bacterial growth, and even biocidal
agents fail in certain cases. These small
microorganisms are not visible to the naked eye, and are
normally only identified when the defect reaches a certain
level.

Medieval leathermaking lives on in AfghanistanA significant proportion of Pakistan’s raw material supply comes from the war-torn country. Traders and hide/skin merchants salt, sort and select for export to Lahore, Karachi, Sialkot or Kasur by the truckload.

World Leather - Apr/May 2010

Variations within hides and skinsThe structure of hides and skins is modified in leather making to make leathers with specified properties. Many of the natural variations found across a skin can be addressed to make both the appearance and physical properties more uniform. The following images indicate the effects of the major processing stages.

Advances in the degreasing of hidesA new lipase degreasing product provides additional benefits such as improved grain tightness, better flatness, cleanliness of the hide, improved dyeing levelness, and has the potential to reduce fogging characteristics and improve hydrophobing. In addition, the replacement of surfactants by lipase offers significant ecological benefits within the degreasing process and in the subsequent treatment of wastewaters.

World Leather - 05 - Aug/Sept 2008

The physical properties across a side and throughout a pack of leatherThe objective of the original study was to determine a location on a piece of leather where the properties could be best related to a complete pack of leathers. These investigations were complex, and produced a vast amount of information. This was presented in a condensed form within the original four papers: these in turn have been used selectively to produce this profile on cross-hide and intra-pack variation.

World Leather - 04 - June/July 2008

Preserving agents in the leather production processDue to extended times in transport and storage, leathers in the wet blue and wet white
condition need protection against bacterial and fungal contamination. This is provided by
synthetic preserving agents. However, triggered by new regulations, these agents and their
use in the leather production process have become the focus of a number of chemical
safety and consumer health issues.

World Leather - 03 - May 2008

Grain down splitting opens the wayThe advent of the “upside down” grain down splitting machine developed several years ago by the Linta Company has made it possible to introduce new feeding and take off systems creating the splitting line. This, as well as the changed roller/knife mounting configuration, takes hands away
from the dangerous band knife edge resulting in much greater safety.

World Leather - 03 - May 2008

A new aqueous transfer coating system for splitsTransfer coating of splits is a well-established process in leather finishing. The physical properties and the optical advantages are significant. The state-of-the-art technology is solvent-based systems, applied either via spraying technology or with rollers and doctor blades onto silicone matrices.

World Leather - 02 - April 2008

The Colombian leather sector: A renaissance banquet of feast and famineThe basis of the Renaissance was the willingness of people to adopt technology and concepts from other cultures. The Colombian leather sector, while very traditional, nevertheless still has a positive Renaissance outlook. Since there has been a very deep relationship between cattle ranching and leather, these facts can help explain the character of the leather sector.

World Leather - 02 - April 2008

Cross-hide variations in physical properties: The determination of the relative degreeThere are considerable variations in the degree of resistance to stretch across the hide of a living animal. The areas of butt, backbone and across the rib cage do not need to
stretch to the same degree as the belly, shanks and axillea parts. In addition, there are variations in the degree of stretch resistance in directions parallel and perpendicular to the backbone.

World Leather - 02 - April 2008

Bangladesh: analysis of the leather, footwear and leathergoods industryThe leather sector is perceived as one of the important economic sectors in Bangladesh. An important feature is that the businesses in this sector are privately owned, with only a few units belonging to multinational companies. Wet blue leather produced by the tanneries is generally sold in the local market, while a considerable volume of crust and finished leather, footwear and leather goods are exported.

World Leather - 02 - April 2008

Cross-hide variations in physical properties:There are considerable variations in the degree of resistance
to stretch across the hide of a living animal. The areas of
butt, backbone and across the rib cage do not need to stretch to the same degree as the belly, shanks and axillea parts.
In addition, there are variations in the degree of stretch resistance in directions parallel and perpendicular to the backbone. This variability is due to the non-uniform layout of collagen fibres within the skin which are aligned to differing degrees in different locations. Thus the starting material for leather manufacture is highly non-uniform. Subsequent manufacturing steps used to make leather will significantly modify this naturally occurring non-uniformity.

World Leather - 01 - Feb/Mar 2008

The physical properties across a side and throughout a pack of leatherThe information presented in this paper provides insight into the fundamental variations in the physical properties found throughout a pack of leather, and across a typical side/hide taken from that pack. The objective of the original study was to determine a location on a piece of leather where the properties
could be best related to a complete pack of leathers. These investigations were complex, and produced a vast amount of information. This was presented in a condensed form within the original four papers: these in turn have been used selectively to produce this profile on cross-hide and intra-pack variation.

World Leather - 01 - Feb/Mar 2008

Advances in the degreasing of hidesA new lipase degreasing product (1) is described that provides good degreasing when compared to the use of standard surfactants. It provides additional benefits such as improved grain tightness, better flatness, cleanliness of the hide, improved dyeing levelness, and has the potential to reduce fogging characteristics and improve hydrophobing. In addition, the replacement of surfactants by lipase offers significant ecological benefits within the degreasing process and in the subsequent treatment of wastewaters.

World Leather - 01 - Feb/Mar 2008

Reducing the amount of salt required for hide and skin preservationIn Pakistan the most common method of curing is by salting. But all of this salt is subsequently removed and most of this enters tannery effluent where it can only be removed under extreme conditions. It is also the major source of salinity found in tannery effluents.

World Leather - 08 - Dec/Jan 2007

The regeneration of used salt from curingOne of the major problems that the leather industry needs to address is the issue of salinity. It is well known that most of the salt component in tannery effluents is generated from the salt used for preservation of hides and skins. There is always an excess of salt applied to ensure a complete cure, so, as a first step to reduce salinity, this surplus can be shaken from the hides and skins before beginning the soaking process. Various methods are used, but the question then arises, what happens to this contaminated salt?

Swelling within the leather manufacturing processSwelling is the increase of volume of a material due to the absorption and/or retention of a solvent, by structural changes or heat. The word implies a shift from the norm, or a comparison to a less distended state.

World Leather - Nov 2006

Technologies to improve the useful area of leatherThe manufacturing of leather is facing diverse challenges including pressure from the eco-toxicity point of view, in the form of stringent new regulations. The measures necessary to deal with these issues add to the cost pressure that tanners are experiencing.

Back to Basics: A framework for leather manufacture. Essay 11Although there is considerable information available on the construction of machines in the tannery, there is very little detail available on the engineering principles involved. Moreover, there is even less information available concerning the way that forces are absorbed by hides and skins under different conditions, and the outcomes from these interactions.

The real cost of a kilo of saltThe following paper provides an overview of a different approach to tanning. The technique is managed in the ‘non-swelling’ pH zone, and thus eliminates the need for salt within the conventional acid pickle. The fibre stabilisation provided – somewhat similar to a pretannage with glutaraldehyde – allows strong leather characteristics, such as those provided by conventional chrome tannage, to be developed within a main tanning or retanning stage.

World Leather - Nov 2005

Optimum chrome tanning of hides and modified Thrublu process for lime-split hidesChrome tanning for a long time enjoyed a unique position amongst tanners and almost 90% of leather produced is chrome tanned. A number of studies have been published suggesting that Chromium(III) itself may be toxic at higher levels and Chromium(VI) is a known carcinogen. So, tanners have to consider how best to modify their tanning process for better exhaustion of chrome and look for alternative means to minimise the impact of tanning on the environment.

World Leather - Nov 2005

Back to Basics: Modifying the skin structure & Hides and skins and mechanical forcesEssay 1: Before first-time drying and the formation of a flat stable substrate, the conversion of hides and skins into leather can be viewed as two distinct stages: the removal of unwanted skin components and the location of specific materials within the collagen structure. Essay 2: The role of the process vessel in leather manufacture is greater than that of a chemical reactor. While chemical reactions take place, considerable forces are applied to the goods undergoing process. The way these forces are received, and the outcome, strongly affects the chemical distribution within each hide or skin.

World Leather - Nov 2005

The replacement of nonylphenol ethoxylates (NPEs) as degreasing agents in wet blue manufactureThe debate continues over whether NP and NPE represent a serious insult to the environment, but there is no longer any doubt about the direction of regulatory control. Increasingly, tanners sourcing wet blue are requiring that it be certified as NPE-free, but a wide range of alternatives now addresses their concerns about substituting NP/NPE technology with more environmentally desirable alternatives. World Leather takes a look.

World Leather - Oct 2005

Removing phospholipids from hides: Looking back on a “New perspective on wet processing”The paper "New perspective on wet processing" was published in World Leather October/November 1993, in which the advantages offered by the removal of phospholipids were discussed. Given that the value of raw hides and leather selling prices - strongly influenced by area and quality - are so important to the tanner, perhaps it's time to re-evaluate this technology.

Bating: gaining area while retaining cutting valuesIt is almost 100 years since Otto Röhm introduced the first
industrial application of an enzymatic product. This was the
bating process of animal hides within leather production, the
enzymes being derived from pancreatic glands. This can be seen

World Leather - Oct 2004

The ruminant stomach: not just sausages and animal foodThe two outer layers of the stomach are of no interest to the leather industry. They may be viewed as the equivalent to the subcutis from hides and skins. The internal layer of the stomach - the gastric mucosa - is the part most suitable for the tanning industry and may be
compared with the corium.

World Leather - Dec/Jan 2003

Weight = area?Within the leather making sector the preference for hide purchases based on area instead of weight have been the subject of debate and investigation. However, neither measurement by
weight nor area provides a truly accurate yardstick for predicting either yields or costings.

World Leather - Nov 2003

Round hides into flat leatherThe need for flat shoe upper material, with predictable stretch, set and ‘memory’, are well appreciated in footwear manufacture. Leather can provide these properties. Nevertheless, given the basic uniqueness of each raw hide, the degree of uniformity achieved as a result of conversion into leather is perhaps surprising.

World Leather - June/July 2003

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